As technology progresses, the manufacturing technique of monitor display is also progressing. Following the technique of light emitting diodes (LEDs), the newest technique of monitor display brought to the market is one that utilizes organic light emitting diodes (OLEDs). Each OLED requires a driver circuit to drive it to emit light. The light can be of either a single color, such as red, green or blue, or even full colors. The advantages of OLEDs are the flexibility, liberation from vision angle restriction, thousands-hour product lifetime and low power consumption. Accordingly, OLEDs are very likely to replace LEDs and become the most popular monitor display in the next generation.
Each pixel of an AMOLED needs an OLED and a driver circuit, so there are ten thousands or even millions of driver circuits in one pad. It is then a complicated task to conclude the functionality of all driver circuits in one pad. FIG. 1, FIG. 2 and FIG. 3 show the common driver circuits configured to drive OLEDs of monitor displays. Referring now to FIG. 1, FIG. 2 and FIG. 3, the method of prior art for testing these driver circuits starts with enabling each one via the write scan line WSL and inputting a certain voltage level via the data line DL after OLEDs are formed. The driver circuit then transfers the voltage level into a current signal I which makes the OLED emit light. According to the voltage level, test engineers determine the OLED's functionality by subjectively observing its luminosity with eyes. If a driver circuit is concluded failed, the OLED having been formed in it is wasted and can not be recovered even though the OLED per se is good. Accordingly, this test method of prior art would result in not only imprecision caused by engineers' subjective decision but also high costs.